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Smoking Behavior and Prognosis After Colorectal Cancer Diagnosis: A Pooled Analysis of 11 Studies.
Pubmed ID
34738070 (View this publication on the PubMed website)
Digital Object Identifier
JNCI Cancer Spectr. 2021 Oct; Volume 5 (Issue 5)
Alwers E, Carr PR, Banbury B, Walter V, Chang-Claude J, Jansen L, Drew DA, Giovannucci E, Nan H, Berndt SI, Huang WY, Prizment A, Hayes RB, Sakoda LC, White E, Labadie J, Slattery M, Schoen RE, Diergaarde B, van Guelpen B, more Campbell PT, Peters U, Chan AT, Newcomb PA, Hoffmeister M, Brenner H
  • Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.
  • Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
  • Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
  • Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
  • Department of Epidemiology, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA.
  • Department of Global Health, Richard M. Fairbanks School of Public Health, Indianapolis, IN, USA.
  • Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
  • Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, USA.
  • Division of Epidemiology, Department of Population Health, New York University School of Medicine, New York, NY, USA.
  • Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA. more
  • Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.
  • Departments of Medicine and Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.
  • Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, PA, USA.
  • Department of Radiation Sciences, Oncology Unit, Umeå University, Umeå, Sweden.
  • Department of Population Science, American Cancer Society, Atlanta, GA, USA.

BACKGROUND: Smoking has been associated with colorectal cancer (CRC) incidence and mortality in previous studies, but current evidence on smoking in association with survival after CRC diagnosis is limited.

METHODS: We pooled data from 12 345 patients with stage I-IV CRC from 11 epidemiologic studies in the International Survival Analysis in Colorectal Cancer Consortium. Cox proportional hazards regression models were used to evaluate the associations of prediagnostic smoking behavior with overall, CRC-specific, and non-CRC-specific survival.

RESULTS: Among 12 345 patients with CRC, 4379 (35.5%) died (2515 from CRC) over a median follow-up time of 7.5 years. Smoking was strongly associated with worse survival in stage I-III patients, whereas no association was observed among stage IV patients. Among stage I-III patients, clear dose-response relationships with all survival outcomes were seen for current smokers. For example, current smokers with 40 or more pack-years had statistically significantly worse overall, CRC-specific, and non-CRC-specific survival compared with never smokers (hazard ratio [HR] =1.94, 95% confidence interval [CI] =1.68 to 2.25; HR = 1.41, 95% CI = 1.12 to 1.78; and HR = 2.67, 95% CI = 2.19 to 3.26, respectively). Similar associations with all survival outcomes were observed for former smokers who had quit for less than 10 years, but only a weak association with non-CRC-specific survival was seen among former smokers who had quit for more than 10 years.

CONCLUSIONS: This large consortium of CRC patient studies provides compelling evidence that smoking is strongly associated with worse survival of stage I-III CRC patients in a clear dose-response manner. The detrimental effect of smoking was primarily related to noncolorectal cancer events, but current heavy smoking also showed an association with CRC-specific survival.

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